1. Field of the Invention
The invention relates to an implement for metering product in an agricultural environment and, more particularly, relates to a metering roller assembly employing an equalizing device configured to enhance the metering of seed or other particulate material for application in an agricultural environment.
2. Discussion of the Related Art
Air seeders are commonly towed by tractors to apply seed, fertilizer, or micro-nutrients or any granular product to a field. It is generally advantageous to tow an air seeder in combination with a tilling implement, one behind the other, to place the seed and fertilizer under the surface of the soil. An air seeder has as its central component a wheeled seed cart which comprises one or more frame-mounted seed tanks for holding product, generally seed or fertilizer or both. Air seeders also generally include a volumetric metering system operable to measure a fixed volume of seed per unit of linear distance and a pneumatic distribution system for delivering the product from the tank to the soil.
The volumetric metering system is configured for distribution of product from the tank to the distribution headers of the seed tubes. The metering system typically includes a meter roller assembly employing augers or fluted cylinders (meter rollers) situated in a meter box assembly secured to below the tank.
Typically the meter box will have a series of outlets known as runs that each leads through the distribution lines of the pneumatic distribution system. The pneumatic distribution system generally includes an air stream operable to carry product metered by the meter roller assembly through the distribution lines to a series of secondary distribution manifolds (“headers”), which in turn distribute product to a group of ground openers mounted on the seeding implement operable to place seed in the ground. The ground openers are configured to evenly deliver the product to the span of ground (the “seedbed”) acted upon by the seeding implement.
The distribution headers ideally have product requirements proportional to the number of ground openers that they service. Since the number of ground openers is often not evenly divisible by the number of distribution headers, one distribution header may service a different number of ground openers than another header. Because a distribution header has one outlet port for each ground opener that it services, headers often have varying numbers of outlet ports. Therefore, in order to evenly distribute product across the width of the seeding implement, product seen by a secondary distribution header servicing ten ground openers, for example, should be less than (⅚) the amount of product seen by a secondary distribution header servicing twelve ground openers. It follows that a metering system associated with the secondary distribution header servicing fewer ground openers should therefore supply a lesser volume of product.
However, conventional air seeders are typically unable to properly ration product to secondary distribution headers, and therefore have problems maintaining an acceptable distribution of seed or fertilizer across the width of the seeding implement. Therefore, it is desirable to devise a metering system which can accommodate varying product requirements seen by individual meter roller assemblies which are driven by a common shaft. It is also desirable to devise a metering system which, in conjunction with a pneumatic distribution system and a seeding implement, provides substantially uniform product distribution across the seedbed.
Various approaches have been used in the past to meter product. One known attempt includes providing a metering system employing a meter roller assembly having metering sections that are divided between fluted (or active) segments and blank (or inactive) segments. Depending on the number of distribution headers, the meter roller assembly will consist of fluted metering sections corresponding to runs which are operational and blank roller spacers extending across the width of the runs which are not operational. Product is then delivered to the distribution headers which are connected to the runs containing the fluted metering sections, and no product is delivered from those runs which are, in effect, blanked off.
Known segmented meter roller systems for the metering of product have several drawbacks. U.S. Pat. No. 5,924,370 discloses a meter roller assembly that employs an equalizing disc to vary the amount of product by each fluted metering roller assembly. However, the equalizing disc is friction fit to the respective metering section. Therefore, the meter roller assembly must be taken apart to reconfigure placement of the equalizing disc on the desired metering section. U.S. Pat. No. 6,158,630 discloses a known segmented meter roller system that employs a meter roller assembly having an equalizing meter device operable to reduce the product flow in each distribution line. However, the configuration of the meter roller assembly needs to be known before assembling the meter roller sections and the respective equalizing meter device. Therefore, the known equalizing meter devices are not easily placed on a roller assembly after the meter roller assembly is factory assembled. Furthermore, the known equalizing meter devices are not detachable and re-attachable to the meter section after factory assembly.
Therefore, a need has arisen to provide an equalizing meter device and a method thereof that enables an operator to readily equalize a distribution of product by a meter roller assembly after factory assembly.